Partially curved lightguide with pupil replicators

Abstract

Techniques for implementing a partially curved lightguide with pupil replicators are disclosed. A partially curved lightguide includes an embedded collimator with surfaces that act to collimate light for display prior to the light encountering a surface in a pupil expansion region of an exit pupil expander. By collimating the light within the lightguide rather than collimating the light prior to entering the lightguide, the requisite volume of a form factor of an AR display is minimized by eliminating select collimating optics and thus enabling a less bulky volume of the AR display in the region of the light source. Using techniques disclosed herein, a partially curved lightguide with pupil replicators is achievable in an eyewear display system having a form factor similar to traditional eyeglasses and curved, thin lenses.

What is claimed is: 
     
         1 . An eyewear display system comprising:
 a curved lightguide; and   a flat lightguide adjoined with the curved lightguide, the flat lightguide providing exit pupil replication.   
     
     
         2 . The eyewear display system of  claim 1 , wherein the curved lightguide comprises a collimation region located between a light source and a pupil replication region along a light propagation path. 
     
     
         3 . The eyewear display system of  claim 2 , wherein the collimation region is configured to collimate display light projected by the light source such that the display light is collimated when transmitted onto a surface of the pupil replication region. 
     
     
         4 . The eyewear display system of  claim 2 , wherein the collimation region is configured to focus the display light at least once along the light propagation path. 
     
     
         5 . The eyewear display system of  claim 2 , wherein the collimation region includes a first freeform surface extending substantially along a total length of the collimation region. 
     
     
         6 . The eyewear display system of  claim 1 , further comprising a tinted substrate. 
     
     
         7 . The eyewear display system of  claim 1 , further comprising an outcoupler configured to adjust a display accommodation distance. 
     
     
         8 . An eyewear display system comprising:
 a light source; and   a lightguide comprising:
 a pupil replication region; and 
 a collimation region located between the light source and the pupil replication region along a light propagation path, wherein the collimation region is configured to collimate display light projected by the light source. 
   
     
     
         9 . The eyewear display system of  claim 8 , wherein the collimation region is configured to project the display light onto a surface in the pupil replication region. 
     
     
         10 . The eyewear display system of  claim 9 , wherein the collimation region is configured to provide the collimated display light onto the surface of the pupil replication region. 
     
     
         11 . The eyewear display system of  claim 8 , wherein the collimation region is configured to focus the display light at least once along the light propagation path. 
     
     
         12 . The eyewear display system of  claim 8 , wherein the collimation region includes a first freeform surface extending substantially along a total length of the collimation region. 
     
     
         13 . The eyewear display system of  claim 8 , wherein the collimation region is located in a portion of the eyewear display system having a curved external form factor. 
     
     
         14 . The eyewear display system of  claim 13 , wherein the pupil replication region includes a flat lightguide. 
     
     
         15 . The eyewear display system of  claim 13 , wherein the pupil replication region is in a portion of the eyewear display system having a curved external form factor. 
     
     
         16 . A method of manufacturing a collimation region for an eyewear display system, comprising:
 positioning a plurality of freeform surfaces along a collimation region including a lightguide, wherein the freeform surfaces are configured to collimate display light projected by a light source.   
     
     
         17 . The method of  claim 16 , wherein the freeform surfaces are discontinuous freeform surfaces, the method further comprising combining the freeform surfaces into a single, continuous freeform surface extending along substantially a total length of the collimation region. 
     
     
         18 . The method of  claim 17 , further comprising diamond turning a substrate to produce the single, continuous freeform surface. 
     
     
         19 . The method of  claim 18 , further comprising embedding the single, continuous freeform surface into a portion of an eyewear display system having a curved external form factor. 
     
     
         20 . The method of  claim 16 , further comprising configuring the freeform surfaces to reflect the display light by total internal reflection.